1. Field of the Invention
The present invention relates to safety shoe toe caps that are applied to shoes, boots or the like to structurally reinforce the shoe toes, thereby enhancing increasing their safety.
2. Description of the Prior Art
Regarding the toe caps in safety shoes, a great importance has hitherto been attached to the strength of the part at the upper of shoes for the protection against the dropping of a heavy material, and hence steel toe caps have been put to practical use. Since, however, safety shoes with steel toe caps are heavy, there occurs a problem with the workability of a person wearing such shoes. For this reason, in recent years, to make safety shoes lighter, toe caps made of a thermoplastic resin reinforced with reinforcing fibers, such as glass fibers, have thus been developed.
Among conventional safety shoe toe caps made of a reinforcing fiber-containing thermoplastic resin, for example, materials used therein are known from the disclosure of Japanese Patent Publication No. 2000-238142. Japanese Patent Publication No. 2000-238142 discloses a safety shoe toe cap that satisfies the strength required in L-class and S-class, which are used for classification of safety shoes according to work divisions in JIS (Japanese Industrial Standard) T 8101. However, although the toe cap disclosed in Japanese Patent Publication No. 2000-238142 is satisfactory from the viewpoint of the strength levels required in L-class and S-class of JIS T 8101, there is a problem that H-class of JIS T 8101, in which a higher strength is required, and the safety shoe standards in CEN Standard (coping with an impact energy of 200 J) cannot be satisfied merely through the material, since there is a limit on the reinforcing fiber content.
Moving on, as disclosed in FIGS. 1, 2 and 5 in Japanese Utility Model Registration No. 2574860, a safety shoe toe cap has a shape in which the tip of the front end part of the toe cap is displaced to the big toe side, this being to make the fit to the inserted foot good, and also in relation to the external shape of the shoe in which the toe cap is installed. However, in the case that the toe cap is subjected to a greater force or load, in relation to the strength the above-mentioned toe cap shape gives rise to a strength imbalance, that is the big toe side is subjected to a larger load, leading to damage to the big toe side rising part.
Furthermore, as disclosed in FIG. 3 in Japanese Utility Model Registration No. 2598209, a safety shoe toe cap is formed such that the top part expands out relative to the base part from the front end side toward the rear end side, this being to make the fit to the inserted foot good, and also in relation to the external shape of the shoe in which the toe cap is installed. However, in the case that the toe cap is subjected to a greater force or load, due to the above-mentioned toe cap shape, the connecting part between the front end rising part and the top part is subjected to a large load, leading to damage at this connecting part. To improve such a problem, an improvement measure has been adopted in which the connecting part is made to be thicker than the other parts (the front end rising part and the top part), but when considering the fit to shoes and feet, there are also limits in such a measure.